Observations on pulsating auroras

Abstract

Observations on pulsating auroras occurring near the equatorward boundary of auroral displays during their postbreakup phase have been made with an image orthicon television system and with photometers. It is found that the pulsating phase of the display is composed of numerous relatively short sequences of pulsations that are restricted to small field-aligned volumes. The luminosity varies synchronously within a given auroral form, but adjacent forms may pulsate asynchronously.